[quote=sailingdog;570107]No, what I am saying is that these units require a fairly hefty AC system, and most small sailboats do not have the electrical capacity to power them for any period of time reasonably. The Pro 500 draws 15.2 AMPS @ 110 VAC... if you need an inverter for that, you're looking at about 150 amps. IMHO, you'd need at least a 2 KW generator to properly feed the watermaker.
Sailingdog: Your right the 500 is not advisable on a small boat with limited power. I think trying to run it from an inverter wouldn't cut it. The 12 volt units I have looked at draw an avarage of 15 amps dc that will give you around 5 gph. If I ran the unit without the gen running you will really use amp hrs. in a hurry. The boat I'm installing the water maker is a 50' and has a 7kw generator. My thinking is if I charge the house bank every other day for a couple of hours I can make about 20-30 gals. From what I've read the 500 draws 15.2 amps FLA I think that means full locked rotor current. After the initial start current surge I think the total draw will be under 10 amps which is no problem for the generator.
Thanks for the info you made a lot of valid points. Where in New England, we sail out of Winthrop just outside of Boston Harbor.